For dissolution of components with relatively low water-solubility and other purposes, solubilizing agents are added to many aqueous ophthalmic formulations. A surfactant can be given as an example of the solubilizing agents used in the field of ophthalmology. It is known that polyoxyethylene castor oil is a nonionic surfactant and is added to an aqueous ophthalmic composition for helping dissolution of other components and other purposes (Patent Literature 1). It is known that polyethylene glycol monostearate is also a type of nonionic surfactant and is added to an aqueous ophthalmic composition for helping dissolution of other components and other purposes.
However, an aqueous composition containing a surfactant is known to easily foaming, and foam is inevitably generated when vibration or impact is applied during production or distribution. In general, to use the aqueous ophthalmic composition in a manner safe on the eyes, dissolution check and foreign matter detection are required in the production steps. However, when foam is generated in the aqueous ophthalmic composition during production, and disappears at low speed, it is hard to distinguish a foreign matter or the like from the foam. Consequently, steps such as dissolution check and foreign matter detection take a long period of time, which may cause a problem of preventing efficient production.
On the other hand, a variety of active components or additives are generally added to an aqueous ophthalmic composition depending on the intended purpose. For example, as a method for stabilizing the viscosity of a composition, there is disclosed a composition that is applicable to mucous membranes, which contains vegetable oil such as sesame oil or castor oil (Patent Literature 2). Vitamins A have been added to an ophthalmic composition ever before for purposes such as reducing eyestrain by promoting eye cell metabolism and respiration, and exhibiting anti-inflammatory action (Patent Literature 3). Chlorobutanol is also known as an additive for an aqueous ophthalmic composition.
However, an effect on an aqueous ophthalmic composition provided when these components and a specific surfactant are added to the aqueous ophthalmic composition cannot be easily predicted.